bug with _read method invocation, or problem with me?

[Dave Clements]

I'm guessing probably me, but truly I know not why. 

Take this mock scenario:

var stream = require('stream');
var readable = new stream.Readable();
readable._read = function (size) {
    console.log(size);
}
readable.read(512);

This (with Node 0.10.21) will log 16384 (the high water mark), instead of the expected 512.

Is this a bug or am I doin it wrong?

If someone in the know can confirm as bug I'll be happen to open an issue

Best,

Dave

[mscdex]

On Sunday, November 3, 2013 5:46:25 PM UTC-5, Dave Clements wrote:

This (with Node 0.10.21) will log 16384 (the high water mark), instead of the expected 512.

https://github.com/joyent/node/blob/v0.10/lib/_stream_readable.js#L320

[David Clements]

Hey thanks mscdex, yeah I see that, so I must be misunderstanding how it works, I would have though that the number passed to read would 

carry through to _read, but instead the read method uses it's n parameter independently and always passes in the high water mark?

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[mscdex]

On Monday, November 4, 2013 6:39:27 AM UTC-5, David Clements wrote:

Hey thanks mscdex, yeah I see that, so I must be misunderstanding how it works, I would have though that the number passed to read would 

carry through to _read, but instead the read method uses it's n parameter independently and always passes in the high water mark?

My guess is efficiency/performance (reading one large Buffer vs reading x individual smaller Buffers possibly needing concatenation to reach n). Another thing to remember is that `read(n)` will return *at least* n bytes.